Cellular uptake and excretion of Zn-tetrasulfophthalocyanine (ZnTSPc) was determined by spectrophotometric analysis of the supernatant. After incubation time of 15, 30, 60, 1440 min. with ZnTSPc, cellular uptake was found to be 1.9 pico g per single Hela cell that corresponds to about 109 molecules of ZnTSPc localized in or on one cell. This indicates that cellular uptake rate of ZnTSPc is fast. Cellular excretion of ZnTSPc was observed after removal of this photosensitizer from the medium. Though 16 percent of ZnTSPc that was taken in or on cells was excreted after 72 hr., no significant differences in efficiency of Photodynamic effects on cell inactivation was observed.
